Shujun Liu 1Ruitao Ma 1Zejie Yu 1,2,3Yaocheng Shi 1,2,3,4Daoxin Dai 1,2,3,4,*
Author Affiliations
Abstract
1 Zhejiang University, College of Optical Science and Engineering, International Research Center for Advanced Photonics, State Key Laboratory for Extreme Photonics and Instrumentation, Hangzhou, China
2 Jiaxing Key Laboratory of Photonic Sensing and Intelligent Imaging, Jiaxing, China
3 Zhejiang University, Jiaxing Research Institute, Intelligent Optics and Photonics Research Center, Jiaxing, China
4 Zhejiang University, Ningbo Research Institute, Ningbo, China
A silicon-based digitally tunable positive/negative dispersion controller (DC) is proposed and realized for the first time using the cascaded bidirectional chirped multimode waveguide gratings (CMWGs), achieving positive and negative dispersion by switching the light propagation direction. A 1 × 2 Mach–Zehnder switch (MZS) and a 2 × 1 MZS are placed before and after to route the light path for realizing positive/negative switching. The device has Q stages of identical bidirectional CMWGs with a binary sequence. Thus the digital tuning is convenient and scalable, and the total dispersion accumulated by all the stages can be tuned digitally from - ( 2Q - 1 ) D0 to ( 2Q - 1 ) D0 with a step of D0 by controlling the switching states of all 2 × 2 MZSs, where D0 is the dispersion provided by a single bidirectional CMWG unit. Finally, a digitally tunable positive/negative DC with Q = 4 is designed and fabricated. These CMWGs are designed with a 4-mm-long grating section, enabling the dispersion D0 of about 4.16 ps / nm in a 20-nm-wide bandwidth. The dispersion is tuned from -61.53 to 63.77 ps / nm by switching all MZSs appropriately, and the corresponding group delay is varied from -1021 to 1037 ps.
silicon photonics dispersion tuning digital tuning multimode waveguide grating 
Advanced Photonics
2023, 5(6): 066005
Author Affiliations
Abstract
1 State Key Laboratory for Modern Optical Instrumentation, Center for Optical & Electromagnetic Research, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
2 ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311200, China
3 Ningbo Research Institute, Zhejiang University, Ningbo 315100, China
A compact on-chip reconfigurable multichannel amplitude equalizer based on cascaded elliptical microrings is proposed and demonstrated experimentally. With the optimized structure of the elliptical microring with adiabatically varied radii/widths, the average excess loss for each channel in the initialized state is measured to be less than 0.5 dB, while the attenuation dynamic range can be over 20 dB. Flexible tunability through the overlapping of the resonance peaks of adjacent wavelength-channels enables even higher attenuation dynamic ranges up to 50 dB. Leveraging the thermo-optic effect and fine wavelength-tuning linearity, precise tuning of the resonance peak can be implemented, enabling dynamic power equalization of each wavelength-channel in wavelength-division-multiplexing (WDM) systems and optical frequency combs. The proposed architecture exhibits excellent scalability, which can facilitate the development of long-haul optical transport networks and high-capacity neuromorphic computing systems, while improving the overall performance of optical signals in WDM-related systems.
Photonics Research
2023, 11(5): 742
作者单位
摘要
1 广西大学资源环境与材料学院, 南宁 530004
2 吉利百矿集团有限公司, 百色 533000
为了提高粉煤灰综合利用附加值, 基于酸碱联合法系统研究从粉煤灰中提取SiO2最佳条件, 并在最佳提取条件下, 提出了新型的简化传统改性白炭黑的制备方法。研究表明, 粉煤灰经过800 ℃预活化后, 在硫酸(固液比(g/mL)为1∶8, 3 mol/L)氛围下保持80 ℃反应90 min后成功转化成硅酸凝胶, 并在质量分数为30%的NaOH作用下溶解提纯, 最后调节溶液pH值得到SiO2含量大于93%(质量分数)的白炭黑, 此时SiO2的提取率为95.7%。此外, 在新型改性白炭黑制备方法研究中, 硅烷偶联剂KH560与形成的白炭黑通过Si—O—Si化学键发生键合, 成功覆盖在白炭黑表面。当改性剂用量为2 mL/g、改性温度为70 ℃、改性时间为60 min时, 获得分散性、疏水性及粒径均匀度较好的改性白炭黑, 其SiO2含量仍达95.97%(质量分数), 比表面积(381.97 m2/g)是未改性白炭黑的2.78倍, 粉体亨特白度达91.43%, 符合A类工业级白炭黑的相关标准。
粉煤灰 改性白炭黑 二氧化硅 硅烷偶联剂改性 酸碱联合法 活化度 fly ash modified silica SiO2 silane coupling agent modification combined acid-base method activation degree 
硅酸盐通报
2023, 42(3): 989
Author Affiliations
Abstract
1 Institute for Fusion Theory and Simulation Department of Physics Zhejiang University Hangzhou 310027 China
2 Key Laboratory for Laser Plasmas and School of Physics and Astronomy, and Collaborative Innovation Center of IFSA (CICIFSA) Shanghai Jiao Tong University Shanghai 200240 China
3 MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter School of Physics, Xi’an Jiaotong University Xi’an 710049 China
4 Technische Universität Darmstadt Institut für Kernphysik Schloβgartenstraβe Darmstadt 64289 Germany
The proton-boron (p 11 B) reaction is regarded as the holy grail of advanced fusion fuels, where the primary reaction produces 3 energetic α particles. However, due to the high nuclear bounding energy and bremsstrahlung energy losses, energy gain from the p 11 B fusion is hard to achieve in thermal fusion conditions. Owing to advances in intense laser technology, the p11 B fusion has drawn renewed attention by using an intense laser-accelerated proton beam to impact a boron-11 target. As one of the most influential works in this field, Labaune et al. first experimentally found that states of boron (solid or plasma) play an important role in the yield of α particles. This exciting experimental finding rouses an attempt to measure the nuclear fusion cross section in a plasma environment. However, up to now, there is still no quantitative explanation. Based on large-scale, fully kinetic computer simulations, the inner physical mechanism of yield increment is uncovered, and a quantitative explanation is given. Our results indicate the yield increment is attributed to the reduced energy loss of the protons under the synergetic influences of degeneracy effects and collective electromagnetic effects. Our work may serve as a reference for not only analyzing or improving further experiments of the p 11 B fusion but also investigating other beam-plasma systems, such as ion-driven inertial confinement fusions.
Laser and Particle Beams
2022, 2022(3): 9868807
作者单位
摘要
1 重庆大学 通信工程学院, 重庆 400044
2 中国空气动力研究与发展中心, 四川 绵阳 621000
3 中国科学院 光电技术研究所, 成都 610209
利用红外跟踪测量系统能够同时获取目标运动信息(包括方位角、俯仰角以及角速度)、目标信号幅度及其成像面积等,提出了一种基于多特征融合的弱红外运动目标跟踪方法。分析了红外成像系统中目标信号特点,得到目标的运动、幅度和面积具有一致性和连续性,符合高斯分布;采用概率数据关联滤波推导量测各特征的关联概率,并根据特征的波动状况确定多特征融合的加权系数,估计和更新目标运动状态。理论分析和实验结果表明:该方法的跟踪精度和稳定性都明显高于仅依靠运动特征关联和依靠运动特征和幅度特征关联的跟踪方法。
微弱红外目标 运动目标跟踪 概率数据关联滤波 多特征融合 infrared dim target moving target tracking probabilistic data association filter multi-feature association 
强激光与粒子束
2011, 23(1): 54

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